Spectral output homogenising apparatus

Abstract

There is described a spectral output homogenising apparatus, the apparatus comprising; a plurality of light sources, wherein the plurality of light sources emits a spectral output; a first medium proximate the plurality of light sources, wherein the first medium is arranged to spatially homogenise the spectral output of the plurality of light sources; a second medium adjacent the first medium, wherein the second medium is arranged to angularly homogenise the spectral output of the plurality of light sources; wherein the spectral output of the plurality of light sources traverses the first medium before traversing the second medium. There is further provided use of an apparatus to homogenise the spectral output of a plurality of light sources and a method of homogenising light from a plurality of sources.

The invention claimed is: 
     
       1. A spectral output homogenising apparatus, the apparatus comprising:
 a plurality of light sources comprising a plurality of LEDs and/or a plurality of laser diodes, wherein the plurality of light sources emits a spectral output; 
 a first medium proximate the plurality of light sources wherein at least a portion of the first medium has a higher refractive index than the external environment medium surrounding the first medium, wherein the first medium comprises a prismatic portion, and, wherein the first medium is arranged to spatially homogenise the spectral output of the plurality of light sources; 
 a second medium adjacent the first medium, wherein the second medium is arranged to angularly homogenise the spectral output of the plurality of light sources; 
 wherein the spectral output of the plurality of light sources traverses the first medium before traversing the second medium, 
 wherein the second medium comprises a holographic diffuser, diffractive diffuser, high efficiency diffuser or beam shaping diffuser for shaping ray angles of the spectral output of the plurality of light sources, and 
 wherein the light sources of the plurality of light sources are arranged symmetrically about the longitudinal axis of the first medium. 
 
     
     
       2. The apparatus of  claim 1 , wherein the sum of the vectors defining the spectral output of each light source of the plurality of light sources defines a first direction. 
     
     
       3. The apparatus of  claim 1 , wherein the longitudinal axis of the first medium is parallel to the first direction. 
     
     
       4. The apparatus of  claim 3 , wherein the longitudinal axis of the second medium is perpendicular to the first direction. 
     
     
       5. The apparatus of  claim 1 , wherein the plurality of light sources further comprises a tungsten-halogen bulb. 
     
     
       6. The apparatus of  claim 1 , wherein the plurality of light sources comprises at least two light sources that emit different discrete wavelength outputs. 
     
     
       7. The apparatus of  claim 1 , wherein the plurality of light sources further comprises a phosphor material for broadening the spectral output of the plurality of light sources. 
     
     
       8. The apparatus of  claim 7 , wherein the phosphor material is positioned between at least one light source in the plurality of light sources and the first medium. 
     
     
       9. The apparatus of  claim 1 , wherein the plurality of light sources is a single row of light sources. 
     
     
       10. The apparatus of  claim 1 , wherein the plurality of light sources is a plurality of adjacent rows of light sources. 
     
     
       11. The apparatus of  claim 1 , wherein the width of the first medium is equal to or greater than the width of the plurality of light sources. 
     
     
       12. The apparatus of  claim 1 , wherein the height of the first medium is equal to or greater than the height of the plurality of light sources. 
     
     
       13. The apparatus of  claim 1 , wherein the first medium is connected to the second medium by a refractive index matching member. 
     
     
       14. The apparatus of  claim 13 , wherein the refractive index of the first medium and the refractive index of the refractive index matching member are substantially identical. 
     
     
       15. A method of using an apparatus to homogenise the spectral output of a plurality of light sources, comprising:
 using the apparatus, the apparatus comprising:
 a plurality of light sources comprising a plurality of LEDs and/or a plurality of laser diodes, wherein the plurality of light sources emits a spectral output; 
 a first medium proximate the plurality of light sources wherein at least a portion of the first medium has a higher refractive index than the external environment medium surrounding the first medium, wherein the first medium comprises a prismatic portion, and, wherein the first medium is arranged to spatially homogenise the spectral output of the plurality of light sources; 
 a second medium adjacent the first medium, wherein the second medium is arranged to angularly homogenise the spectral output of the plurality of light sources, 
 wherein the spectral output of the plurality of light sources traverses the first medium before traversing the second medium, 
 wherein the second medium comprises a holographic diffuser, diffractive diffuser, high efficiency diffuser or beam shaping diffuser for shaping ray angles of the spectral output of the plurality of light sources, 
 wherein the light sources of the plurality of light sources are arranged symmetrically about the longitudinal axis of the first medium, and 
 
 wherein a current to the plurality of light sources is provided such that light is emitted from at least two light sources within the plurality of light sources. 
 
     
     
       16. A method of homogenising light from a plurality of sources, comprising:
 providing an apparatus comprising:
 a plurality of light sources comprising a plurality of LEDs and/or a plurality of laser diodes, wherein the plurality of light sources emits a spectral output; 
 a first medium proximate the plurality of light sources wherein at least a portion of the first medium has a higher refractive index than the external environment medium surrounding the first medium, wherein the first medium comprises a prismatic portion, and, wherein the first medium is arranged to spatially homogenise the spectral output of the plurality of light sources; 
 a second medium adjacent the first medium, wherein the second medium is arranged to angularly homogenise the spectral output of the plurality of light sources, 
 wherein the spectral output of the plurality of light sources traverses the first medium before traversing the second medium, 
 wherein the second medium comprises a holographic diffuser, diffractive diffuser, high efficiency diffuser or beam shaping diffuser for shaping ray angles of the spectral output of the plurality of light sources, 
 wherein the light sources of the plurality of light sources are arranged symmetrically about the longitudinal axis of the first medium; and 
 
 providing a current to the plurality of light sources such that light is emitted from at least two light sources within the plurality of light sources. 
 
     
     
       17. The method of  claim 16 , wherein the method further comprises the step of monitoring the spectral output of at least one light source within the plurality of light sources. 
     
     
       18. The method of  claim 17 , wherein the step of monitoring the spectral output of at least one light source within the plurality of light sources comprises continually monitoring the spectral output of at least one light source within the plurality of light sources.